2BHU

Crystal structure of Deinococcus radiodurans maltooligosyltrehalose trehalohydrolase

Summary for 2BHU

• Entry DOI: 10.2210/pdb2bhu/pdb
• Related: 2BHY 2BHZ
• Descriptor: MALTOOLIGOSYLTREHALOSE TREHALOHYDROLASE, 2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, TRIETHYLENE GLYCOL, ... (5 entities in total)
• Functional Keywords: trehalose, alpha-amylase, hydrolase, protein-carbohydrate complex, desiccation resistance
• Biological source: DEINOCOCCUS RADIODURANS
• Cellular location: Cytoplasm (By similarity): Q9RX51
• Total number of polymer chains: 1
• Total formula weight: 67498.33

Authors

Timmins, J.,Leiros, H.-K.S.,Leonard, G.,Leiros, I.,McSweeney, S. (deposition date: 2005-01-18, release date: 2005-03-31, Last modification date: 2025-04-09)

Primary citation

Timmins, J.,Leiros, H.-K.S.,Leonard, G.,Leiros, I.,Mcsweeney, S.
Crystal Structure of Maltooligosyltrehalose Trehalohydrolase from Deinococcus Radiodurans in Complex with Disaccharides
J.Mol.Biol., 347:949-, 2005

PubMed Abstract: Trehalose (alpha-D-glucopyranosyl-1,1-alpha-D-glucopyranose) is a non-reducing diglucoside found in various organisms that serves as a carbohydrate reserve and as an agent that protects against a variety of physical and chemical stresses. Deinococcus radiodurans possesses an alternative biosynthesis pathway for the synthesis of trehalose from maltooligosaccharides. This reaction is mediated by two enzymes: maltooligosyltrehalose synthase (MTSase) and maltooligosyltrehalose trehalohydrolase (MTHase). Here, we present the 1.1A resolution crystal structure of MTHase. It consists of three major domains: two beta-sheet domains and a conserved glycosidase (beta/alpha)8 barrel catalytic domain. Three subdomains consisting of short insertions were identified within the catalytic domain. Subsequently, structures of MTHase in complex with maltose and trehalose were obtained at 1.2 A and 1.5 A resolution, respectively. These structures reveal the importance of the three inserted subdomains in providing the key residues required for substrate recognition. Trehalose is recognised specifically in the +1 and +2 binding subsites by an extensive hydrogen-bonding network and a strong hydrophobic stacking interaction in between two aromatic residues. Moreover, upon binding to maltose, which mimics the substrate sugar chain, a major concerted conformational change traps the sugar chain in the active site. The presence of magnesium in the active site of the MTHase-maltose complex suggests that MTHase activity may be regulated by divalent cations.

PubMed: 15784255
DOI: 10.1016/J.JMB.2005.02.011

Experimental method

X-RAY DIFFRACTION (1.1 Å)